1. Field
Embodiments of the present invention relate to optical scanners, specifically optical scanners located on an ingestible endoscopic device
2. Related Art
Modern electronic imaging systems typically utilize a two dimensional focal plane array (FPA). However, this requires the use of a single optical lens element with a stop that is circularly symmetrical in two dimensions to focus the image onto all of the imaging FPA. Currently, small imaging systems such as those used in camera pills for biomedical cameras, as well as for security and industrial applications, are limited in resolution by the pixels in their FPA chip. As a result, the current camera pills for gastric intestinal (also referred to herein as endoscopic) examination have a relatively low resolution of, for example, 300×300 pixels. This results in images that provide extremely limited details and cannot be enlarged significantly for improved diagnostic analysis.
These systems are further impaired with the orientation of the array such that the field of view of the camera pill is continuous and fixed. For example, a camera pill may only look down the central axis of the pill and GI tract thereby presenting the center of the field of view as having very little to no useful image data. Additionally, these camera pills typically require extremely wide angle “fish-eye” lenses to image the tissue along the intestinal wall with the result that the images are distorted and non-uniformly illuminated.
Further, use of a fish-eye lens generates images where the information of the condition of the inside wall of the GI tract is only contained in a ring of pixels at the peripheral region of the image. In this situation the center region of the image shows a view down the length of the intestine and contains little or no useful information. This results in images where the most important data is presented on a small fraction of the pixels in a focal plane imaging array such as a CCD or CMOS imager. This reduction in the effective resolution is exacerbated by the presentation of the image in a distorted circular appearance with the most outer edge visible being brightly lit and close to the imaging array while the rest of the intestinal wall surface is progressively further away from the camera and progressively dimmer in illumination.
Additionally, the images of interest to a physician are images of the intestinal wall, not the forward-looking view down the GI tract. The ability to scan the intestinal walls is thus preferred over traditional camera pill imaging. The ability for the capsule to image the entire tubular wall and the size and electrical connections required for the focal plane array define that the image array be set so that the imaging surface is perpendicular to the axis of the pill.